KR20050097964A - Tubular reactor for carrying out catalytic gas-phase reactions and method for operating said reactor - Google Patents

Abstract

The invention relates to a tubular reactor for carrying out catalytic gas-phase reactions, containing a catalyst tube bundle (8) that is traversed by the relevant reaction gas mixture, is filled with a catalyst, extends between two tube sheets (4, 148) and around which flows a heat transfer medium contained within a surrounding reactor jacket (6). Said reactor also comprises gas entry and discharge hoods (2; 60) that cover the two tube sheets for supplying the relevant process gas to the catalyst tubes and for discharging the reacted process gas from the catalyst tubes. The reactor is characterised in that together with all the parts that come into contact with the process gas mixture, it is designed to have an appropriate strength for withstanding the deflagration and explosive pressures that are to be taken into account during its operation. The volume available to the process gas mixture prior to its entry into the catalyst tubes is restricted as much as possible in construction and flow engineering terms. The inventive reactor permits a higher charge of an explosion-critical component to be added to the process gas that is to be treated in a risk- free, economical manner and an explosion-critical range in the current gas composition to be traversed during the start-up phase of the reactor.

Description

TUBULAR REACTOR FOR CARRYING OUT CATALYTIC GAS-PHASE REACTIONS AND METHOD FOR OPERATING SAID REACTOR}

The present invention relates to a tubular reactor according to the preamble of claim 1 and to a method of operating said tubular reactor.

Tubular reactors of this kind are known, for example, from DE 100 21 986.1. In this particular case, however, the deflagration critical element of the process gas for the reaction fed into the reactor is added, in part, directly in front of the reactor tubes or in the reactor tubes to reduce the risk of deflagration. In addition, the volume so far given to this element is kept small by the interior of the gas introduction hood of a general and approximately domed shape. This measure stems from the following perception:

1) It is desirable to make the supply of process gas as large as possible with deflagration critical elements (eg oxygen and carbon) in order to achieve the largest possible production performance with respect to the size of the reaction plant.

2) The risk of deflagration increases over time, in addition to the gas supply, that both components stay together.

So far, attempts have been made to protect bursting disks in the reaction plant against large damages caused by deflagration. However, if one wants to continue to increase supply and output, using bursting discs is not enough due to the increased risk of deflagration. The use of expensive rupture discs in the event of deflagration requires a relatively long period of repair and downtime. When the rupture plate ruptures, it is connected to a pressure wave reaching outward, which spreads far and wide as a binge. This makes it hard to endure several times. In addition, harmful gases may be emitted. In addition, it is difficult and time consuming to restart the reactor each time after replacing the bursting disc after deflagration. In particular, in order to achieve a high feed rate in the operating state at start-up, it is necessary to avoid passing gaseous compounds currently supplied to the reactor through the deflagration zone.

The deflagration range can be represented by a two or three component schematic (see Henrikus Steen's Handbuch des Explosionsschutzes), WILEY-VCH Publishing, 1st Edition (2000), page 332). Is an inert gas (eg nitrogen) added for dilution. It has been found that the deflagration risk is only present inside the windowed area of the schematic, which depends on pressure, temperature and geometry.

According to DE 198 06 810 A1, in order to prevent dangerous side effects and ignition and explosion, the temperature of the gas introduction tube sheet can be reduced by an insulating layer applied on the gas introduction tube sheet.

According to EP 1 180 508 A1, the continuous measurement and change of the process gas mixture at the start-up of the reactor circulates around the deflagration range, with inert gas being added first. The inert gas is replaced by a process gas that has already reacted more and more after the reaction takes place.

1 is a half longitudinal cross-sectional view of a gas introduction side tube sheet comprising a gas entry hood of a tubular reactor according to the present invention;

FIG. 2 is a cross-sectional view of the edge region of the tube sheet shown in FIG. 1, at the height of line II-II of FIG. 1, FIG.

Figures 3 and 4 are views similar to Figures 1 and 2, detailing an embodiment with internals in a conventional gas introduction hood for the supply of process gas;

FIG. 5 is a half longitudinal cross-sectional view of a gas introduction side tube sheet similar to FIG. 1, a conventional gas introduction hood in the shape of a shell similar to FIG. 3, and an interior provided therein; FIG.

6a) to 6f) are enlarged views of embodiments of semipermeable packing as can be seen in FIG.

7 is a longitudinal sectional view of another embodiment similar to FIG. 5;

8 is a cross-sectional view of a post disposed inside of a tubular reactor according to the present invention for the tube sheet on the gas introduction side above all;

9 is a longitudinal cross-sectional view of a gas introduction hood similar to FIG. 5 provided with a coolant and / or a heating agent;

FIG. 10 is a view similar to FIG. 7 with the devices in connection with the process gas supplied to the reactor;

11 is a cross sectional view of an alternative process gas supply in connection with the gas introduction hood according to FIG. 1;

Under this basis the object of the present invention is to enable, among other things, to continue to increase the supply of process gas reached for processing in a risk free and economical manner.

The object is achieved by the features of claim 1 by the invention, and the features of the dependent claims contribute to it.

The second object of the invention is to operate economically using the special features of the tubular reactor according to the invention. This object is achieved by the methods 48 and 49 respectively.

The reactor according to the invention, on the one hand, can be safely operated with a deflagration critical supply of the process gas reached for processing, and on the other hand it can pass through the ignitable zone at startup. This makes the start-up step significantly easier and faster.

Hereinafter, deflagration and detonation will be distinguished. However, it is not distinguished in the above mentioned document EP 1 180 508 A1. Unlike detonation, which occurs in one place and causes a pressure wave to be transmitted at subsonic velocity, the explosion is a very sudden and stronger process. Explosions are mainly based on explosions which can occur over a certain starting distance depending on the structure, in addition to the more specialized gas mixtures.

Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.

Figure 1 shows the gas introduction end of the tubular reactor of the present invention for carrying out a catalytic gas phase reaction in the deflagration and explosion critical zones. Specifically, in FIG. 1, a specially formed gas introduction hood 2, a tube sheet 4 lying under the gas introduction hood, a reactor jacket 6 connected to the tube sheet, and a ring shape A catalyst tube bundle 8 (only implied by dashed lines in FIG. 1) and a gas introduction pipe connection 10 leading to the gas introduction hood 2 can be seen. Usually, a tube bundle 8 comprising a suitable catalytic filling is flowed around by a flowable heat transfer medium inside the reactor jacket 6 (when operating in any way) and over the reactor jacket A suitable temperature profile is maintained along the tube and excess heat of reaction is discharged.

As can be seen in FIG. 1, the rigid edge flange 12 is used to install and pack a gas introduction hood to the tube sheet 4. Except for the gas introduction hood 2, the gas introduction hood 2 is relatively flat and shaped like a trumpet mouthpiece. Thus, there is a flat gas distribution region 14 between the gas introduction hood and the tube sheet 4, which is constantly introduced (ie without interruption, without a kick site or the like). It is connected to the pipe connection 10. The installation of the gas introduction hood 2 in the tube sheet 4 is made by screws (only indicative in the drawings) arranged around it.

The gas distribution region 14 is sized such that the process gas supplied to the catalyst tube in the gas distribution region 14 flows into the catalyst tubes in the same shape as possible (ie, especially without vortex, without retention). At this time, the allocation of the gas distribution region is made so that the radial flow elements or the static pressure in the process gas is constant in the radial direction. Mixed forms are also possible. That is, the shape of the trumpet mouthpiece of the gas introduction hood 2 on the other side can also be close to the ring elements (not shown) which are approximately conical. In order to ensure that the gas flow does not change when entering the gas distribution region 14, a visible drawbar 16 is arranged below the gas introduction pipe connection 10 and above the tube sheet 4. The flow drawbars at the same time form a displacer in order to prevent the gas from hitting head-on in the middle of the tube sheet 4. In this embodiment, the lowest height of the gas distribution region 14 is determined to a height defined by the sealing ring 18, by which the gas distribution region 14 can be sealed from the outside. The lowest height of the gas distribution zone is determined during the design of the reactor and should not be zero at any position around the reactor, for example due to the unevenness of the hood 2 and / or the tube sheet 4. . If necessary, the hood and / or tube sheet should be surface facing in the same place.

Radial outer spacing of the outermost catalyst tubes (eg 20), dead volume 22 inside the gas distribution region 14 (without disturbing gas introduction into the outermost catalyst tubes). Because this is not structurally inevitable, and because such dead volumes can cause unwanted retention of the processing gas, this site is intended to push the processing gas out of the dead volume 22 or at least dilute it with a deflagration non-critical composite. Measures are taken. In other words, an inert gas is injected in connection with the deflagration reaction of concern. For example N ₂ And incidental matter produced when the progress of the reaction run for the inert gas, the operation of (for example CO _2), and sometimes may be simply air or a compound of such a gas.

According to FIG. 1, the associated gas (hereinafter referred to as flushing gas) passes through a ring conduit 24 around the tube sheet 4, and the regular gas along the circumference of the tube sheet 4. It is injected through channels 26 branching inwardly at intervals and nozzle holes 28 branching up in these channels 26.

As can be seen in FIG. 2, the nozzle holes 28 are inclined in the circumferential direction of the tube sheet 4. This is to form a radial flow element with the gas exiting the tube sheet and to flow the entire dead volume 22 in this manner.

3 and 4 show another embodiment of the gas introduction end of the tubular reactor according to the invention. Inside the dish-shaped conventional gas introduction hood (only the edge 40 is shown), the interior 42 defining the gas distribution region 14 can be seen. The same parts as in Fig. 1 and Fig. 2 have the same reference numerals.

Unlike the embodiment described above, here the ring conduit 44 for the flushing gas which has to enter the dead volume 22 surrounds the edge 40 of the gas inlet hood. Thus, the passing channels 46 pass radially through the edge 40 as compared to the channels 26. Channels 46 are connected to adapter 48 with nozzles 50 directed into the edge 40 to flow dead volume 22 as completely as possible and tangentially for the release of gas. It leads.

5 is provided with an interior 42 in the interior of a dish-like gas introduction hood similar to FIG. 3. As shown, the interior 42 freely hangs and secures to the gas introduction hood 60 (to be exact, shell 62 of the gas introduction hood) via a stud 64 and a gas introduction pipe connection 10. do. If necessary, the deflagration and explosion forces appearing in the gas distribution region 14 are fixed in such a way that they are introduced into the shell 62. In order to accommodate these forces as well as possible, the shell 62 has a dome-shaped shape.

In this embodiment, the interior 42 consists of a slightly conical washer 66 and a profile ring 68 rounded inside and bottom, with a semipermeable packing 72 at the edge 70 of the interior. Is supported on the tube sheet 4. In contrast, the gas introduction hood 60 is filled with a flushing gas for the dead volume 22 outside of the interior 42. The flushing gas here enters the dead volume 22 uniformly through the semipermeable packing 72 to the extent that it is supplied to the gas introduction hood 60 through the conduit 74.

Similar to that described in DE 44 07 728 CI, in this embodiment the gas introduction hood 60, more particularly, the rigid edge 40 of the gas introduction hood has a weld lip seal 76 against the tube sheet 4. It is sealed by lip-seal. However, a sealing ring such as the sealing ring 18 in the above embodiments may be used. In order to act as a confining fluid, the flushing gas is subjected to an overpressure on the outside air as well as on the gas distribution region 14.

6A) through 6F) illustrate various embodiments that may be considered the semipermeable packing 72 of FIG. 5. According to FIG. 6 a), the semipermeable packing 72 is pressed into an annular groove 84 of the tube sheet 4 by a slightly compressible material with holes, such as a ring-shaped protrusion 82 of the interior 42. It consists of a ring of circular cross section made of graphite or a ring 80 having an elliptical cross section. According to FIG. 6b), the packing 72 is grooved in the form of C and preferably consists of a ring 86 of metal. The ring has a plurality of radial or slightly tangential grooves 88 regularly distributed on its outer face towards the tube sheet 4. According to FIG. 6C), the semipermeable packing has radial or slightly tangential holes 92 in the protrusion 94, similar to the protrusion 82 of FIG. 6A), and a rigid and resilient sealing ring similar to the sealing ring 18. It consists of 90. According to FIG. 6D), the packing 72 is formed of a ring 98 made of metal or other hard-elastic material and basically provided with a radial or slightly tangential groove 96 with a circular cross section. do. The ring rests on an annular groove 100 inside the protrusion 102 similar to the protrusion 82. According to FIGS. 6E and 6F, bent cross section sheet metal profile rings 104 or 106 are used as the packing 72, and towards the tube sheet 4 as shown in FIG. 6E). It may have a groove 108 similar to the groove 88. In order to enable a somewhat larger average cross section for the flushing gas, the profiling rings can be bent against an overpressure acting on one side.

FIG. 7 shows a configuration similar to that of FIG. 5, but the flushing gas penetrates the tube sheet 4, the weld lip seal 122 similar to the weld lip seal 76, and two metal plates which are not leaking. Radially outside the interior 42 into the ring-shaped space 120 between the rings 124, 126. The essentially cylindrical metal plate ring 126 formed at the edges of the interior 42 is formed of a tube sheet to form a semipermeable packing towards the gas distribution region 14, similar to the semipermeable packing 72 of FIG. 5. Loosen in the annular groove 128 of (4). In this embodiment, the studs 64 of FIG. 5 are replaced with a cylindrical metal plate 130 with a small hole.

8 shows how the gas introduction side tube sheet 4 can be supported towards the gas discharge end of the reactor when deflagration or explosion occurs in the gas introduction zone. In the example shown, the strut 140 consists of a multi-winged metal part, essentially made of two metal plates 141 arranged in a cross shape, the metal plates preferably being loosely tubed. It engages with the grooves 142 on the underside of the seat 4 and is located in the appropriate radial line of the tube bundle 8. In addition, as shown, the center of the tube sheet 4 is supported on the metal plates 141 by oblique braces or metal plate cones 146 inside the tubeless intermediate region 144 near the aperture. In this way, only one metal plate 141 is possible depending on the situation. Thus, it can be saved especially with two passages without a tube. Cylindrical, prismatic, or pyramidal metal parts may replace the plate cone 146.

As shown, but not necessarily the strut 140 may extend to a gas output-side tube sheet 148, or to a separation disc. In any case, however, the strut must be able to introduce a bearing force to the reactor jacket 6. For the adjustment of various thermal expansions, the metal plates are recessed at the connection with the metal plates, such as 141, the longitudinal stress relief slot 150 and the reactor jacket 6, especially in the vicinity of the gas introduction side tube sheet 4. Has 152. In addition, the metal plates may have small holes and may be replaced by scaffolding structures wherever suitable for the purpose, either from a fluid technical standpoint or because of weight savings. In particular, the advantage of having the support 140 disposed on the gas discharge tube sheet 148 is that it can be passed through the aperture to the gas discharge chamber or against deflagration pressures that may be created by reignition there. The tube sheet can also be supported.

According to DE 198 06 810 A1, the gas introduction side tube sheet 4 may be thermally insulated (not shown) to keep the gas distribution region 14 "cold" to reduce the tendency of deflagration or explosion.

9 shows coolant channels 160 provided in the gas introduction hood 2 and in various places in the gas introduction hood for the same purpose in a configuration similar to FIG. 5 or FIG. 7. The coolant channels are also used as heating channel, especially when starting the reactor, and may contribute to the elimination of thermal stress.

FIG. 10 shows the gas introduction end 170 of the reactor according to FIG. 7 with said means for preparation of process gas. In this embodiment, the second process gas at any location 174 of the main pipe 172 for the process gas base element (such as the so-called main flow) at a suitable temperature and under a suitable pressure. Urea (e.g., hydrocarbon gas) is supplied in an amount not yet capable of generating compounds of deflagration capability. In contrast, other portions of the second or other process gas elements at 176 and 178 may be added following a check (non-return) valve arrangement (180). Behind the last feed-in point 178, process gases are located in areas where they can explode.

The entire process gas elements transported are then mixed at multiple coordinates carefully (ie, avoiding disturbance motion, for example) through successive multiple mixers 182, 184, 186. At this time, care should be taken to avoid discontinuities during wiring. In addition, the conduit 188 between the non-return valve arrangement 180 and the gas introduction hood 2 is kept as short as possible to prevent high deflagration pressures from occurring. This applies especially when the start of the explosion is concerned. The non-return valve arrangement 180 prevents the pressure wave that would otherwise occur in the conduit 188 and subsequently into the pipe 172 and cause damage in these supplies. The non-return valve arrangement 180 is located in the chamber 190, which simultaneously forms the desired pressure relief volume for the pressure wave. Chamber 190 may have any shape and may have any volume directed upwards. Other chambers may enter the same place in a further step. A mixer may be provided (not shown), preferably after the first feed-in point 174, and in front of the non-return valve arrangement 180, if desired. However, in order to achieve good mixing in this manner, supply 174 may be preceded by a substantial amount of non-return valve arrangement 180. On the other hand, in some cases, following the non-return valve arrangement 180, only one additional supply (eg 176) and only one mixer may be provided.

Non-return valve arrangement 180, chamber 190, conduit 188, mixers 182-186 contained therein, feeders, reactor itself are the most serious deflagration pressures or explosions that can occur in or around the worst case. It is natural to be equipped with a hardness that can withstand pressure. As noted above, this is important to avoid explosions and deflagrations to the greatest extent possible, despite all the above measures.

FIG. 11 is in principle similar to the configuration of FIG. 10, but with the gas introduction hood 2 according to FIG. 1 and the curved part in the mixers and conduits 188 is omitted. The curved part is omitted very short in this case. In any case, the mixers interfere with the gas flow. Thus, the process gas is more likely to deflagrate. In particular, the mixer is to be avoided as much as possible in order to produce a deflagration critical process gas mixture. It also attempts to reduce the starting distance that is considered for the development of the explosion.

 According to FIG. 11, the non-return valve arrangement 180 is arranged on the axis of the gas introduction pipe connection 10 in the center above the gas introduction hood 2, with only one instead of both supplies 176, 178 of FIG. 10. Precision injection site, or a precision injection device 192 is provided. On the other hand, there are no mixers. The precision injection device 192 has a plurality of injection devices 194 distributed over (ie at least 5) preferably 50 pro m 2 or more conduit cross section. Similar to the injection devices at the catalyst tube inlet of DE 100 21 986 A1, the injection devices are configured to provide nozzles and individual throttling elements and / or swirl the injected processing gas element. Can be formed. In this way, the supply of the second process gas element (eg hydrocarbon) can be very delicate and regular. Thus, mixers are not needed to achieve homogeneous process gas flow.

In principle, the injected process gas element can be in flow and gas form and can be cold or heated. In flow form it is possible to inject the injected treatment element through an inert gas. Similar to what is done when fueling the cylinder space of a combustion engine, injection can be made with a high pressure to cause partial vaporization with a blowout in any case.

Jacket heating may be provided in the injection zone, in line with which the conduits for the second treatment element may be heated or insulated.

The strength measurement of the reactor elements depends on the type and concentration of material to be processed. In general, the strength measurement of reactor elements is performed during stationary operation. Is done. When starting to operate the tubular reactor of the type described above, care should be taken not to exceed the deflagration strength quoted for operation in any case. Normally, you start with just one, ie each process gas foundation element (mainstream). When a certain mass flow is reached, a second process gas element is added. In operation, if an inert gas such as, for example, CO ₂ is generated in the plant itself, it can basically be drawn up and started to operate according to EP 1 180 508 A1. Whether the inert gas should be transported additionally at start-up or whether the intensity of deflagration or the intensity of explosion can be reduced, for example only through changes in pressure and temperature, depends on the process design.

As already mentioned, the starting can lead to an area that is already ignitable. As in operation, other parameters, such as pressure and temperature, in addition to the process gas mixture may also be considered at startup. Pressure and temperature affect the deflagration and explosion reactions. It is possible to change the pressure and temperature during startup. That is, the pressure at startup can be reduced while the temperature rises in the gas distribution region 14. At the end of the start-up phase, pressure and temperature rise to the specified operating values.

If the tubular reactor is operated in the lower deflagration zone with low deflagration risk and low deflagration pressure and recycle gas is added to the mainstream as inert gas in the reactor, the start-up can be made as follows:

First, air or oxygen is supplied to the main pipe 172 as mainstream. The hydrocarbon stream then begins to be added via injector 194 (FIG. 1). There is no risk of deflagration while the hydrocarbon concentration is low. Similarly, the recycled gas consists essentially of only mainstream materials. Reactants are already generated in the subsequent starting process by adding hydrocarbons. The recycle gas thus already contains an inert gas (eg carbon dioxide). The hydrocarbon streams become strong while the starting process continues. The mainstream does not reach the critical state at any time because it already contains a significant share of the inert gas. Basically, it is intended to avoid explosion zones at startup in this way. This is to enter the deflagration area after reaching sufficient processing stability.

In principle, the same applies to operation in the upper deflagration region. In this case, however, hydrocarbons are usually transported as mainstream via pipe 172. On the other hand, hydrogen is supplied through the injection device 194.

According to the state of the art, the tubular reactor of the present invention can preferably be used for oxidation process, hydrogenation process, dehydrogenation process, nitrification process, alkylation process and the like, and above all ketone, methylisobutyl Ketone (methy isobutyl ketone), mercaptan, isoprene, isoprene, anthraquinone, o-cresol, ethylene hexane, furfurol, acetylene ( acetylene, vinyl acetate, isopropyl chloride, naphthalic acid anhydride, vinyl chloride, oxo alcohol, pyrotol, styrene, methane acid Nitrile (methan acid nitrile), polyphenylene oxide, dimethyl phenol, pyridine aldehyde, terban, alphaolefine, vitamin B6, hydrocyanic acid production of anic acid, aniline, methan acid nitral, difluoromethane, 4-mehyl-2-pentanone and tetrahydrofuran, in particular,

Oxidation of dimethylbenzene (m, o, p) to the corresponding monoaldehydes and dialdehydes,

Oxidation of dimethylbenzene (m, o, p) to the corresponding monocarboxylic and dicarboxylic acids or their aldehydes,

Oxidation of the corresponding monoaldehydes, dialdehydes, trialdehydes in trimethylbenzene,

Oxidation of trimethylbenzene to the corresponding monocarboxylic acid, dicarboxylic acid, tricarboxylic acid, or anhydride thereof,

Oxidation from durene to pyromellitic acid anhydride,

Oxidation of gamma-picoline or beta-picoline to gamma-picoline carbaldehyde or beta-picoline carbaldehyde,

Oxidation of gamma-picoline or beta-picoline to isicotinic acid or nicotinic acid,

Oxidation of propene to acrolein,

Oxidation of acrolein to acrylic acid,

Oxidation of propane to acrolein,

Oxidation of propane to acrylic acid,

Oxidation of butane to MSA,

Oxidation of raffinate to MSA,

oxidation of i-butene to methacrolein,

Oxidation of methacrolein to methacrylic acid,

Oxidation of methacrolein to methyl methacrylate,

oxidation of i-butane to methacrolein,

oxidation of i-butane to methacrylic acid,

Ammonoxidation from dimethyl benzene (m, o, p) to the corresponding mononitrile and dinitrile,

Ammoxidation from trimethyl benzene to the corresponding mononitrile, dinitrile or trinitrile,

Ammoxidation from propane to acrylonitrile,

Ammoxidation from propene to acrylonitrile,

Ammoxidation from beta-picoline to 3-cyano-pyridine,

Ammoxidation of gamma picoline to 4-cyano pyridine,

Oxidation of methanol to formaldehyde,

Oxidation of naphthalene and / or o-xylene (in some mixing plants) to phthalic anhydride,

Oxidation of ethane to acetic acid,

Oxidation of ethanol to acetic acid,

Oxidation of geraniol to citral,

Oxidation of ethene to ethylene oxide,

Oxidation of propene to propylene oxide,

Oxidation of hydrogen chloride to chlorine,

Oxidation of glycol to glyoxal, and

Used to hydrogenate MSA to butanediol.

Claims (49)

A catalyst tube bundle 8 through which a reaction gas mixture passes, is filled with a catalyst and extends between two tube sheets 4,148 and around which a heat transfer medium contained in the reactor jacket 6 flows, A tubular reactor for carrying out a catalytic gas phase reaction comprising a gas introduction hood and a gas discharge hood (2; 60) covering two tube sheets for supplying a tube and for discharging the reacted process gas from the catalyst tube, A tubular reactor, characterized in that it is formed to have adequate strength to withstand the deflagration and explosion pressures that must be considered during operation, including all components in contact with the process gas mixture. The method of claim 1, The volume given to the process gas before entering the catalyst tube is kept as small as possible from a structural and flow technical point of view. The method according to claim 1 or 2, A dead volume in which the process gas can be stopped, in whole or in part, in the volume given to the process gas before entering the catalyst tube, as far as possible from a structural and flow technical point of view. The method according to any one of claims 1 to 3, Inert flushing with respect to the reaction in a place where structural volumetric flow is inevitable from a structural and flow technical point of view where a dead volume at which the process gas can be stopped, in whole or in part, at a volume given to the process gas before entering the catalyst tube is avoided. A tubular reactor, characterized in that the gas is injected. The method of claim 4, wherein The flushing gas is characterized in that the tubular reactor is injected radially out of the catalyst tube bundle (8) at the edge of the gas introduction side tube sheet (4). The method of claim 5, The flushing gas is injected with a tangential flow element. The method according to any one of claims 1 to 6, At least in the supply of the already treated reaction gas, the redirection and above all discontinuities are prevented as much as possible. The method according to any one of claims 1 to 7, The gas introduction hood (2) is a tubular reactor, characterized in that it is formed to have a central gas inlet in a flat funnel shape. The method of claim 8, The gas introduction hood (2) is formed in the shape of a trumpet mouthpiece round, tubular reactor, characterized in that it is formed flat toward the edge. The method according to any one of claims 1 to 7, A conventional funnel shaped funnel 42 is disposed coaxially and flat in the conventional dish-shaped gas introduction hood 6, in which the central opening is hermetically connected to the gas inlet, and the edge of the gas inlet is the gas inlet tube sheet. A tubular reactor characterized by being sealed towards the edge of (4). The method of claim 10, The interior 42 is formed in the shape of a trumpet mouthpiece round, tubular reactor, characterized in that it is formed flat toward the edge. The method according to claim 10 or 11, wherein The inner part (42) is preferably supported in the gas introduction hood (60) at a plurality of regularly distributed positions. The method according to any one of claims 3 to 10 or 12, The packing (72) passes the gas at a limited edge of the interior (42), and the flushing gas is injected through the packing. The method of claim 13, The packing 72 is a tubular reactor, characterized in that consisting of a semi-permeable material such as graphite tissue. The method of claim 13, The packing (72) is characterized in that it has separate gas passage channels such as holes (92) or grooves (88; 96; 108). The method according to claim 13 or 14, The packing (72) is a tubular reactor, characterized in that it consists of moldings (86; 104; 106) which can optionally be bent against overpressure. The method according to any one of claims 13 to 16, The packing (72) is connected to the outer side space, characterized in that the flushing gas is supplied through the space tubular reactor. The method of claim 17, The space is defined by a radial inner packing (72) and a radial outer packing (76). The method of claim 18, The flushing gas is under an overpressure relative to outside air. The method according to any one of claims 17 to 19, The space is basically a tubular reactor, characterized in that consisting of the remaining volume of the gas introduction hood (60). The method according to any one of claims 1 to 20, If the gas introduction hood (2; 60), the gas introduction side tube sheet (4) and / or the enclosure (42) are present, the enclosures (42) are connected to each other via weld lip seals (76; 122). Tubular reactor. The method according to any one of claims 1 to 21, The gas introduction hood (2; 60) is fixed to the gas introduction side tube sheet (4) via a stud disposed around. The method according to any one of claims 1 to 22, The gas introduction hood (2; 60) and / or the interior of the gas introduction hood (42) can be cooled and / or heated. The method of claim 23, Tubular reactor, characterized in that the gas introduction hood (2; 60) and / or the interior of the gas introduction hood (42) has channels (160) through which a coolant or heating agent can pass. The method according to any one of claims 1 to 24, On the gas introduction side tube sheet (4), a tubular reactor, characterized in that a barbed flow drawbar (16, drawbar) is arranged which is tapered towards the gas inlet. The method according to any one of claims 1 to 25, The gas introduction side tube sheet (4) is supported in a reactor jacket (6, reactor jacket) in the direction of the gas discharge side tube sheet (148). The method of claim 26, A support is a tubular reactor, characterized in that the strut consists at least in part of a multi-winged metal part about the reactor longitudinal central axis. The method of claim 26 or 27, The metal part is basically a tubular reactor, characterized in that consisting of at least one diagonally disposed metal plate (141). The method of claim 27 or 28, With a ring-shaped catalyst tube bundle 8, the strut consists essentially of additional metal parts of cylindrical, prismatic, conical or pyramidal form, in part of the inner space of the catalyst tube bundle. A tubular reactor, characterized in that supported by a metal part having a plurality of blades. The method according to any one of claims 26 to 29, wherein The strut has a tubular reactor, characterized in that it has a plurality of longitudinal strain relief slots (150) and / or strain relief recesses (152). The method according to any one of claims 26 to 30, The column is characterized in that the tubular reactor extends to the gas outlet side tube sheet (148). The method of any one of claims 26 to 31, The strut is characterized in that the tubular reactor is loosely adjacent to each tube sheet (4; 148). 33. The method according to any one of claims 26 to 32, The column is characterized in that the column is engaged with the recess (142) of each tube sheet (4; 148). The method according to any one of claims 1 to 33, The gas introduction side tube sheet (4) is a tubular reactor, characterized in that the heat treatment. The method according to any one of claims 1 to 34, The gas introduction hood (2; 60) has a first supply (174) for a second process gas element that is added to the first process gas element with respect to the gas supply, and then a second or other process gas element. At least one other feed (176,178; 192) for the remainder followed by a tubular reactor. 36. The method of claim 35 wherein At least one mixer (182, 184, 186) followed by at least the last feed (178). The method of claim 35 or 36, At least one second feed formed from a precision injection device (192) having a plurality of injection devices (194) distributed over a channel cross section. The method of claim 37, The injection device (194) is provided with individual nozzles and / or vortex forming elements. The method according to any one of claims 35 to 38, At least one of the feeds (174, 176, 178; 192) is characterized in that the process gas element is formed in a flow form so that it can optionally be heated to be received or to heat itself. The method of claim 39, And said supply (174,176,178; 192) has means for injecting a fluid process gas element. 41. The method of claim 39 or 40, And said supply (174,176,178; 192) is capable of atomizing and / or vaporizing a process gas element. The method according to any one of claims 35 to 41, The feed (174,176,178; 192) and / or the conduit of the feed has a heating agent and / or is insulated. The method according to any one of claims 35 to 42, Tubular reactor, characterized in that there is provided a non-return valve arrangement 180 between the first and second supply (172,174). The method according to any one of claims 35 to 43, Tubular reactor, characterized in that there is a pressure relief volume between the first and second feeds (174,176). The method of claim 44, Wherein said pressure relief volume is formed at least in part by a chamber (190) containing a non-return valve arrangement (180). The method according to any one of claims 1 to 45, A tubular reactor, characterized in that it is used for oxidation, hydrogenation, dehydrogenation, nitrification, alkylation and the like. The method of claim 45, Ketone, methyl isobutyl ketone, mercaptan, isoprene, anthraquinone, o-cresol, ethylene hexane, fur Furolol, acetylene, vinyl acetate, isopropyl chloride, naphthalic acid anhydride, vinyl chloride, oxo alcohol, pyrotol , Styrene, methan acid nitrile, polyphenylene oxide, dimethyl phenol, pyridine aldehyde, terban, alphaolefine Production of vitamin B6, hydrocyanic acid, aniline, methan acid nitral, difluoromethane, 4-mehyl-2-pentanone and tetrahydrofuran, in particular, Oxidation of dimethylbenzene (m, o, p) to the corresponding monoaldehydes and dialdehydes, Oxidation of dimethylbenzene (m, o, p) to the corresponding monocarboxylic and dicarboxylic acids or their aldehydes, Oxidation of the corresponding monoaldehydes, dialdehydes, trialdehydes in trimethylbenzene, Oxidation of trimethylbenzene to the corresponding monocarboxylic acid, dicarboxylic acid, tricarboxylic acid, or anhydride thereof, Oxidation from durene to pyromellitic acid anhydride, Oxidation of gamma-picoline or beta-picoline to gamma-picoline carbaldehyde or beta-picoline carbaldehyde, Oxidation of gamma-picoline or beta-picoline to isicotinic acid or nicotinic acid, Oxidation of propene to acrolein, Oxidation of acrolein to acrylic acid, Oxidation of propane to acrolein, Oxidation of propane to acrylic acid, Oxidation of butane to MSA, Oxidation of raffinate to MSA, oxidation of i-butene to methacrolein, Oxidation of methacrolein to methacrylic acid, Oxidation of methacrolein to methyl methacrylate, oxidation of i-butane to methacrolein, oxidation of i-butane to methacrolein acid, Ammonoxidation from dimethyl benzene (m, o, p) to the corresponding mononitrile and dinitrile, Ammoxidation from trimethyl benzene to the corresponding mononitrile, dinitrile or trinitrile, Ammoxidation from propane to acrylonitrile, Ammoxidation from propene to acrylonitrile, Ammoxidation from beta picoline to 3-cyano-pyridine, Ammoxidation of gamma picoline to 4-cyano pyridine, Oxidation of methanol to formaldehyde, Oxidation of naphthalene and / or o-xylene (in some mixing plants) to phthalic anhydride, Oxidation of ethane to acetic acid, Oxidation of ethanol to acetic acid, Oxidation of geraniol to citral, Oxidation of ethene to ethylene oxide, Oxidation of propene to propylene oxide, Oxidation of hydrogen chloride to chlorine, Oxidation of glycol to glyoxal, Production of hydrogenation from MSA to butanediol, A tubular reactor, characterized in that used in. 48. A method of operating a tubular reactor according to any one of claims 1 to 47, The tubular reactor is operated by adding at least one other process gas element to the first process gas element, taking into account occasional deflagrations and explosions during fabrication operations. Characterized in that the method. 48. A method of operating a tubular reactor according to any one of claims 1 to 47, For the start up of the reactor, the concentration of process gas elements and optionally other parameters are continuously assigned such that the intensity of deflagrations and explosions that occur in some cases does not exceed the intensity of deflagrations and explosions that can be tolerated in the operating state. Characterized in that the method.